G4TWIST is an implementation of GEANT 4 in the OpenScientist environment. OpenScientist allows the integration of several packages, and as such takes advantage of many open-source packages, particularly, visualization packages. The combination of these visualization packages with GUIs and scripting allows the creation of an environment that is user friendly and easy to use. This environment is particularly handy when building a detector geometry. In addition to the vivid 3-d images, the user can move, rotate, zoom in and out continuously, all with the click of a mouse. This makes the task of verifying and debugging complicated geometries very straight forward. Scripts can also be used to create buttons that allow the user to display each detector component with the click of a button, thereby, further simplifying the task of geometry verifications.
Although the OpenScientist implementation allows other functionalities, the G4TWIST code is restricted to the geometry part, and in this sense this implementation is only intended for visualization.